Compound for filling holes in cast iron



aten te d Nov. '15, 1927.

UNlTEfD STATES PATENT OFFICE.

rm mam owns, or DANVILLE, PENNSYLVANIA.

comounn non FILLING- HOLES In cns'r IRON. 4 3

Ho Drawing.

This invention relates to a compound in the form of paste, adapted to be usedfor filling up the holes and defects in iron castings, preparatory to enameling the same.

l3 It is a welldrnown fact that no matter how carefully and skillfully the casting operation is performed, certain holes or depressions Will'be formed to a greater or less extent in the surface of the casting due. to it accumulated particles of sand'or slag, so that it is often impossible to cover them suf ficiently by enamel alone to secure a smooth and uniform surface.

The objectfof the present invention is to provide a compound which maybe applied to the casting in much the same manner as putty is applied to holes or defects in wood surfaces preparatory to painting or varnishing the same, and it is especially important that the compound be so constituted that it will not be adversely affected by the extreme heat necessary to bake the enamel, and will, in fact, form a union with the casting so as to make, for all intents and purposes, a solidified whole.

The body of the composition, which constitutes the subject matter of my invention, consists of fine iron filings. These filings are made preferably from soft pig iron after the temper has been removed therefrom, so as to make it easily reducible. These filings are then passed through a fine sieve, and are then mixed with a sufiicient quantity of a solution of sulphate of magnesia in water to form a compound of about the same consistency as putty. The solution of sulphate of magnesia is composed of approximately one part of sulphate of magnesia to twelve parts of water. The water acts as a solvent for the sulphate of magnesia, and the solution acts as a vehicle for the iron filings so as to form a compound which may be easily molded and worked into the holes in the casting, leaving a smooth'surface to which the enamel may be applied.

The compound can be kept indefinitely by placin it in air tight metallic tubes or other air tig t containers; and in case it should become dry, Water may be applied to restore it to proper-consistency.

The usual method of applying the enamel of 1200 to 1250 F.

application filed December 9, 1 92%. Serial No. 75$,855.

is by spraying it on the surface of the casting after the'latter has been rendered smooth and uniform by the use of the compound.

The enamel is then baked at a temperature Cast iron surfaces after they have been treated in this manner and enameled will be perfectly smooth, and no defects in the castings will be discernible. The sulphate of magnesia serves as a cement'to hold the filings in place until the first coat of enamel is applied, and also replaces a certain amount of enamel which is burned up in the baking process. The water serves to give the compound a pasty consistency so that it may be easily applied. The iron filings, together with the sulphate of magnesia, upon the application of heat during the'baking process, causes such a union of the compound withthe casting as to make an integral whole, resulting in a smooth, even surface, which can not be obtained by the use of enamel alone. I am, however, unable to state whether or not the compound actually forms a chemical combination with the consisting of finely divided particles of iron mixed with a quantity of sulphate of magnesia dissolved in water.

2. A plastic compound, consisting of finely divided particles of iron mixed with a suficient quantity of sulphate of magnesia dissolved in water to form a stiff paste.

3. A compound for the purpose described, consisting of soft iron filings mixed with a suflicient quantity of a solution" of sulphate of magnesia in water to form a stiff paste, said solution being approximately inthe proportion of one part sulphate of magnesia to twelve parts water.

In testimony, that I claim the foregoing as 100 my own, I have hereto alfixed my signature.

FRANKLIN NORRIS GHILDS. 

